when I bought my ST165, the previous owner was bragging about all the rear bushings being replaced with the poly bushings and I thought..."Oh crap..." for a good reason...
I had bad experience with poly bushings on my old Volvo 240 turbo. I replaced the OEM front and rear bushings with a complete set of poly bushings from ipd (a well renowned performance place for Volvos...) anyway...the handling was absolutely horrendous for my daily street driver...the back was soooo touchy and sooo unsettled especially in the rain...almost scary and definitely unsafe...for street...every small road imperfections would upset the back to the point that the back would loose the grip...every "recommended speed" exit from the highway would present a challenge for my 240 turbo. I changer the tires with high performance ones, it helped a bit...I even changed the rear springs rate with a softer ones, it didn't help too much. Than I start reading a lot about the car dynamics, about the suspension settings and so on and I start thinking a little bit more about the poly bushings for street applications. I decided to change ALL the ipd poly bushings back with the OEM Volvo ones. After this I just couldn't believe how well the car handled. The previous challenging highway exits were a joke now even at double the speeds with a lot more confidence...I even upgraded the rear springs with just a little bit harder than OEM ones but by not too much...the car was soooo much better now...anyway...
back to my ST165 with poly bushings in the back... I drove the car with those poly bushings for few months experiencing almost the same feeling as with my old 240 turbo with polys...
Well ...I said "enough is enough !!!" ...I parked the ST165 and switch to my old reliable, fun and safe 240 turbo as my daily driver and ordered the OEM Toyota rear bushings... pretty much ALL of them (I kept only the swaybars bushings in poly...). After installing the OEM rear bushing to my ST165, the car changed dramatically in better. HUGE improvement in ANY aspect of the handling. Now the car felt incomparable much better than before; the back was now actually following the front the way is suppose to do not like before when, again any minor road imperfection would upset dramatically the rear.
The bottom line is that the poly would be good on the track but for street (daily driver...) they are disastrous...for me at least. I think there are a lot of variables involved here but I had two personal experience regarding poly bushings for street applications that allows me to say safely that OEM is definitely (without any doubt...) way to go for street. I just cannot stress more what a tremendous difference made going back to the OEM bushings for both of my cars, 240 turbo and the ST165...night and day...
So,...I though you may want to know somebody else's experience with the rear poly bushings...

paladek,
while you make a clear case against poly bushes on a daily driver, reading your comments also makes me wonder about using them on a dedicated track car. If you can't take highway on/off ramps at speed how is the car going to handle a high speed sweeper? While most tracks don't have potholes while some roads do, I don't make a point of driving over the curbs around town. A nervous car isn't going to give the driver the confidence they need to pitch around at the track.

My experience switching to poly in my 165 was pretty much opposite that of paladek.

My 165 (#1) with old OEM bushings required little steering corrections on off ramps and canyon cruises. Mid-corner stability just wasn't very good. The switch to poly completely eliminated that and I can now (and have been for years) hitting those same off ramps faster and with more confidence.

My other 165 (#2) with lower mileage (~72k) OEM bushings is not as bad as 165 (#1) was when I swapped in the poly, but it is still bad in comparison.

88st165 wrote:for those that switched to poly, did you use the spherical bushings like thoe ones posted or did you use poly in their place?

I did. The spherical bearings have absolutely no play at all. They move on there axis as need for the suspension. The poly would probably cause a problem there. I think maybe there was a problem with lube on his bushings or maybe they were torqued down with the suspension off the ground?

-----André B.1991 ST185 (down but not out)1990 ST185 (lost, but not forgotten)1996 RZN140 (the daily)2004 Yamaha R6 (needs a battery)

88st165 wrote:for those that switched to poly, did you use the spherical bushings like thoe ones posted or did you use poly in their place?

I did. The spherical bearings have absolutely no play at all. They move on there axis as need for the suspension. The poly would probably cause a problem there. I think maybe there was a problem with lube on his bushings or maybe they were torqued down with the suspension off the ground?

I take it we never found a solution for the bushing at the other end where the camber adjustment is right? I know in this thread Gary had mentioned a 205 bushing, but obviously thats not a solution for us here..

Maybe I wasn't too clear in the other posting...so here are some details...
There is a quite simple (pure physics, dynamics..) reason that the polyurethane bushings (at least the one on the market right now...the single axis rotation bushing...) CANNOT be use for the rear suspensions arms 1 and 2 as correctly "Gary ST165" mentioned. You can, however use them pretty much anywhere else. Or, rephrasing....one can still use the polys even for the rear arms 1 and 2 providing that they are willing to spend enormous amount of time in tweaking the rear suspension.
Here is the reason:
Remember that in all the 4wd celicas (165, 185, 205) the rear subframe is FLOATING with respect of the chassis, hence with respect of the front suspension arms...in fact, the rear subframe mounting mechanism to the chassis allows quite a big of variations (at least few mm; I would say more than 5mm...) in the plane parallel with the attachment points. So, in other words, the rear suspension geometry can be easily altered just by moving the rear subframe a bit around the mounting points. This thing is definitely not good, in fact quite bad... Remember, the 4wd celica was NOT designed as a real 4wd car from the get go, instead, the 4wd celicas appeared as the response to Toyota's need for a 4wd car for their WRC rally campaign...So the Toyota engineers had slapped a rear dif carrier with all the necessary stuff to a fwd existing celica chassis. By doing that the Toyota engineers were faced with quite few problems...and they found solution to all of those...good and clever solutions...They quickly figured out that by adding a floating rear subframe with the rear suspension arms attached to it, there will be quite few variations from car to car and even on the same car once the subframe was unbolted from the chassis and put back on the chassis (after changing the differential or subframe bushings for example...); these variations would cause a possible heavy laterally preload on the rear suspensions arms 1 and 2 IF single axis rotation type of bushings were to be used for these both rear suspension arms. So, the Toyota engineers ingeniously used SPHERICAL bushings. Those bushings does allow for small variation in the rear suspension geometry WITHOUT laterally loading them. ...Simple as that !!!.
This explains why some of you (lucky...) guys have no problems with poly rear bushings, while others not so lucky (..I among those...???!!!) have had such a bad experience with them...Is just the difference between the rear arms being laterally loaded vs nonloaded...(or minimal load...)
The bottom line: the one axis rotation bushings (...poly bushings as they are designed today...) are NOT TO BE USED for the rear suspension arm 1 and 2. They simply are not designed for this application. However, they can still be used provided that extensive tweaking the subframe position to the chassis will be done to ensure NO lateral load is applied to the rear suspensions arms. (it is critically important that absolutely ZERO laterally load be applied on the rear suspension arms, otherwise the rear suspension will react quite unpredictable and highly accelerated bushings wear will be present...)
So when I said "for track use..." I meant to say that on a car prepared specifically for track use there are extensive suspension mods anyway, so for these cars spending extensive amount of time for tweaking the suspension is pretty much expected ...

I should also clarify that I did replace the spherical bearings when I put in the rest of the poly bushings. In fact, I'm the guy who pioneered the replacement of those spherical bearings. Prior to my write-up here, people were replacing the whole carrier assembly in order to get those spherical bearings.

So, yeah, I'm not advocating putting poly in place of those spherical bearings, only in place of the OEM rubber bushings.